Subject-matter of the invention is a method of controlling mass flow in the form of multi layer stream of rod-shaped articles, particularly tobacco industry products, and a device for controlling the said flow.
In production lines manufacturing rod shaped tobacco articles, like cigarettes, filters or cigarettes with filters already stuck on, in the course of the production process the said products cover a considerable distance after leaving the manufacturing machine before they are placed in packets in the packing machine or in the stores. The flow usually takes place in a multi layer ordered stream, which eliminates deformation or destruction. There is a need for handling the stream of products in order to convey it to or from different devices used in the production line. For this purpose, on the path of horizontal conveyor carrying the articles, near-perpendicular channels which connect one horizontal conveyor with another horizontal conveyor or receiver are made. Rod-shaped articles fill fully vertical channels and principally horizontal conveyors, which is a condition determining the state of their order. The flow on a horizontal path is usually forced by a conveyor, while the flow in angularly situated channels usually takes place by gravity. The said flow handling consists many times in cutting off the channel in which the articles flow or in directing the stream of articles to another receiving device, with the necessary condition being that rod-shaped articles are as little damaged as possible when controlling the flow. Devices for stopping the flow of a stream and/or changing its direction are known in the state of the art. For instance, from the U.S. Pat. No. 5,217,101 a device is known for connecting mass flows of rod-shaped articles in the tobacco industry in which a plate or a shaped gate swivel-mounted on the axis situated near the connection point of horizontal conveyor with angular channel is used, with the plate or shaped gate being opened when a too small flow of the stream is detected or a need for connecting the streams arises. The shaped gate may form simultaneously an interim mini-store stockpiling the overflow of rod-shaped articles. Another device for transporting rod-shaped articles is known from the U.S. Pat. No. 5,529,164. In this construction, a slidable plate provided with a flexible tape which in case of need is angularly inserted in accordance with the direction of stream flow in the upper part of the vertical channel thus shutting off its inlet is used, with the flexible tape becoming a part of the bottom wall of horizontal conveyor. A temporary overflow of articles is absorbed by a generally known pocket formed by two self-aligning arms arranged in the upper wall of horizontal conveyor in the channel axis, with arm ends being connected by a membrane. On the other hand, in the description of the U.S. Pat. No. 4,986,408 concerning a device for handling rod-shaped articles, an attempt to use a slidable plate arranged parallel to the path of horizontal stream of rod-shaped articles that separates this stream from the vertical channel was made. The invention presents different technical solutions for the plate itself as well as for the means of its activation. A drawback of this solution is the possibility of damaging rod-shaped articles during horizontal inserting of the plate into the area of the channel filled with these articles. A similar principle of cutting off the flow by a tape-type element inserted between rod-shaped articles above the inlet of vertical channel was shown in the U.S. Pat. No. 4,553,660. A solution nearest to the subject-matter of the applied invention was presented in the description of the U.S. Pat. No. 7,044,286 concerning the separation of streams of multi layer flows of rod-shaped articles. According to the described method, rod-shaped articles are removed, for the purpose of separation, from the border area of horizontal conveyor or angularly situated channel, which becomes a passive stream, to the area of horizontal channel or conveyor, which becomes an active stream, and the amount of removed articles is equal to the volume of a corresponding part of a cylinder with a radius corresponding to the width of horizontal conveyor and/or the width of the channel, with cylinder walls parallel to its axis separating non-parallel streams from each other. Said articles may be also closed in a niche with the shape of horizontal conveyor or channel made inside the rotating cylinder, across the axis of rotation, with the rotation axis of the cylinder being in the symmetry plane of the niche, and besides the rotation axis of the cylinder being in the symmetry plane of the horizontal conveyor and/or channel, and the articles being shut by a rotation of the cylinder. Presented valve device for separating streams according to said invention consists of a valve in form of a cylinder or its sector situated in the crossing point of horizontal conveyor and channel, with the rotation axis of the valve being the axis of the cylinder and overlapping the intersection edge of upper plane of the wall of horizontal conveyor with the plane of side wall of the channel or the intersection edge of the plane of the bottom wall of horizontal conveyor with the plane of side wall of the channel, or the rotation axis of the valve being in symmetry plane of the channel and/or horizontal conveyor in a distance from the intersection edge of side wall of the channel with the wall of horizontal conveyor equal to or a little greater than the cylinder radius, while inside the cylinder a through niche with the shape of the channel and/or horizontal conveyor is made, with the rotation axis of the valve being in symmetry plane of the niche. The above solution partly eliminates the degradation of the outer layer of articles in passive stream and facilitates the flow of multi layer stream with any speed, with the removal of articles to active stream preventing pressure buildup in the stream, and the removal of articles from the border area not causing a disturbance of their ordered reciprocal arrangement. Removed articles are indeed replaced by the cylinder wall on which the stream flows, however, when inserting the sharp edge of cylinder valve in the stream of articles, which does not have a possibility of shock absorption, a degradation of a part of articles being in direct contact with said edge may occur.